Gearing



DSG 12, 1939- B. R. GRANBERG ET Al. 2,183,514

Filed Nov. 18, 1958 ATT RNEY.

Patented Dec. 12, 1939 UNITED STATES PATENT FWB GEARING nois Application November 18, 1938, Serial No. 241,086

6 Claims.

The invention relates to speed change gearing of the type used in machine tools for driving spindles. It is the general object of the invention to provide new and improved gearing of this Ype- ` Another object is to provide a new and im proved gearing for driving a machine tool spindle at a number of preselected speeds extending over an extremely wide range.

Another object is to provide new and improved gearing of the pick-off type wherein a number of pairs of gears are provided to furnish definite spindle speeds and are reversible to provide additional speeds, together with means for enabling the use of the pick-olf gears to obtain a still larger number of speeds extending over a wider range. v Further objects will become readily apparent from the following detailed description taken in connection with the accompanying drawing, wherein:

Fig. 1 is a fragmentary rear elevation (partly in section along the line I I of Fig. 2) of the spindle head of a milling machine embodying a preferred form of the invention.

Fig. 2 is a fragmentary section along the line 2-2 of Fig. l, expanded for the' purpose of rendering the disclosure clearer.

Although we have illustrated in the drawing and shall herein describe a preferred form of' the invention as embodied in the spindle gearing f for a milling machine, it is to be understood that various modifications and alternative constructions may be adopted without departing from the Aspirit and scope of the invention as defined in the appended claims.

As illustrated in the drawing, the preferred form of the invention is embodied in the spindle supporting element or head I0 of a milling ma chine. A cutter supporting spindle I'I is rotatably mounted in the element Ill by means of anti-friction bearings I2, I3 and I4. The forward bearings I3 and I4 are carried in a sleeve or quill I 5 which is slidablv mounted in a cylindrical bore I6 in the supporting element to facilitate adjustment of the spindle longitudinally of its axis. During such adjustment, the rear bearing I2 slides longitudinally in a cylindrical bore I'I. o

As illustrated in the drawing, a power driven shaft i8 is rotatably mounted in the element I0 by means of anti-friction bearings I9 and 20. At its forward end, the shaft I8 carries a multiple grooved pulleyZI which is driven from an electric motor 22 by means of a plurality of belts 23.`

In order to obtain an extremely wide range of spindle speeds with a relatively small number of sets or pairs of pick-01T gears, an arrangement of shafts and gearing is provided enabling the use of the pick-off gear sets on either of two power driven vshafts which rotate at different speeds. The power driven shaft I8, for example, is utilized for supporting pick-off gears when it is desired to operate the spindle II at speeds in the higher portion of its range. A second power driven shaft 25 is arranged to support one of the pick-off gears of each set when it is desired to operate the spindle II at speeds in the lower portion of its range.

The drive from either of the power driven shafts to the spindle includes an intermediate shaft 26 which is rotatably mounted in antifriction bearings 21 and 28. As illustrated in Fig. 2, the left hand end of shaft 26 and the left hand end of the power driven shaft I8 project through an interior wall 28 of the supporting element Ill and are fashioned on their outer or left hand ends for the reception of pick-off gears, such as 29 and 3D. The projecting ends of the shafts are preferably provided with keys 3l and 32 which engage in suitable keyways in the pickoif gears, and have threaded ends for the reception of nuts 34 and 35 which when tightened function to hold the pick-off gears on the shaft. The bearings I9 and '21 are mounted in cylindrical openings 36 and 38 in the wall 28. The drive from the intermediate shaft 26 to the spindle Il comprises an elongated spiral pinion lill formed on the shaft 26 and a corresponding spiral gear 4I secured to the spindle II, the pinion 40 being elongated so as to permit of the longitudinal adjustment of the spindle I I. As illustrated in Fig. 2, the drive from the power driven shaft I8 to the spindle is through the pick-off gears 3l) and 29, intermediate shaft 2S, pinion 4I), and gear 4I.

It is the practice in manufacturing machine tools equipped with pick-off gears to provide a specified number of sets or pairs of pick-ofi gears so that the purchaser will have on hand the necessary gears for changing the speed of the spindle within a definite range. The range is `determined by that set or pair of gears which is made up of the largest gear and smallest gear. Such a set vis illustrated in the drawing wherein the smallest gear 363 is mounted on the power driven shaft I8, kand the gear 29 is mounted on the intermediate shaft 26. This arrangement, therefore, provides for the lowest spindle speed possible. By reversing the pick-off gears so that Smallest gear 3G is mounted on the intermediate shaft 26 and the largest gear 29 is mounted on the power driven shaft i3, the spindle Il will be driven at the highest available speed. It is to be understood that the other sets of picko gears must all be designed to fit the ends of the shafts I8 and 2G and the predetermined spacing between the axes of the shafts. These other sets are generally provided in sizes ranging between those illustrated and two gears of substantially equal diameter.

In order to increase the range and the number of speeds at which the spindle il may be driven without requiring additional sets of pickoff gears, the invention includes the second drive shaft hereinbefore mentioned. This power driven shaft is rotatably mounted in anti-friction bearings ll and i5 and has a projecting end 41 carrying a key i8 and a threaded portion 49. The actual relationship of the shaft 25 to the intermediate shaft 2G is shown in Fig. l. Here again the bearing 45 is mounted in the wall 28' whereas the bearing Se is mounted in an upstanding integral portion 59 of the supporting element I0. As shown in Fig. l, the shaft 25 is positioned somewhat to one side of the intermediate shaft 2G, the axis of the shaft 25 being located at a distance from the axis of the shaft 26 exactly equal to the distance between the axis of the shaft i8 and the shaft 25. This is to permit the driving gear of each set of pick-off gears to be mounted either on the power driven shaft I8 or on the power driven shaft 25, the other pickoff gear of each set being mounted at all times on the intermediate shaft 26.

The range of spindle speeds obtainable when the driving pick-off gear is mounted on shaft 25 is determined by gearing intermediate the shaft i8 and the shaft 25. As illustrated herein, this gearing comprises a pinion 55 formed on the shaft i8 and meshing with a gear 5B keyed on a short shaft 5l, and another pinion 58 on the shaft 5T which meshes with a gear 59 keyed to the shaft 25. The shaft 5l is rotatably mounted in anti-friction bearings 6G and (il, bearing 60 being supported in the wall 28 and the bearing 8l being supported in the portion 50 of the supporting element IB. With the double reduction gearing shown intermedate shaft i8 and shaft 25, the spin-dle speeds available when shaft 25 is used for mounting the driving pick-off gear are substantially lower than those available when the shaft i8 is used for mounting the driving pick-off gear.

In order to change the gearing set-up of the machine as illustrated in the drawing, it is merely necessary to remove the nut 35 and the driving pick-off gear 3i) from the shaft I8 and to replace these parts on the shaft 25. The drive from the power driven shaft I8 to the spindle H will then be through the gearing 55, 56, 58, 5S, pick-off gears 30 and 29, shaft 26, pinion 4Q and gear Lil.

t is believed readily apparent that the invention as disclosed herein provides a simple gearing arrangement for obtaining a Wide range of spindle speeds with a minimum number of sets of pick-off gears. For any specied number of sets of pick-off gears, it is possible to obtain double the number of spindle speeds obtainable heretofore. Preferably, a detachable cover B3 is pro- .,vided to enclose the ends of the shafts and pickoi gears.

We claim as our invention:

l. In a milling machine, in combination, a spindle supporting element, a spindle rotatably mounted on said element, a first power driven shaft rotatably mounted on said element on an axis parallel to and spaced from the spindle axis, an intermediate shaft rotatably mounted on said element, means forming a gear connection between said intermediate shaft and said spindle, said first power driven shaft and intermediate shaft having projecting ends arranged to receive pairs of pick-off gears to form a direct drive between said rst power driven shaft and the intermediate shaft, and means for driving the intermediate shaft by the same pick-off gears at another speed comprising a second power driven shaft rotatably mounted on said element on an axis parallel to said intermediate shaft spaced therefrom a distance equal to the distance between said intermediate shaft and said first power driven shaft and having one end projecting to receive a pick-off gear positioned to mes with a corresponding pick-off gear on said intermediate shaft and means for driving said second power driven shaft from said first power driven shaft comprising reduction gearing.

2. In a milling machine, in combination, a spindle supporting element, a spindle rotatably mounted on said element, a first power driven shaft rotatably mounted on said element on an axis parallel to and spaced from the spindle axis, an intermediate shaft rotatably mounted on said element, means forming a driving connection between said intermediate shaft and said spindle, said nrst power driven shaft and intermediate shaft having portions arranged to `receive pairs of pick-off gears to complete a drive connecting between said first power driven shaft and the intermediate shaft, and means for alternatively driving the intermediate shaft by the same pickoif gears at another speed comprising a second power driven shaft rotatably mounted on said element on an axis parallel to said intermediate shaft spaced therefrom a distance equal to the distance between said intcrmedate shaft and said first power driven shaft and having a portion arranged to receive a pick-off gear positioned to mesh with a corresponding pick-off gear on said intermediate shaft and means for driving said second power driven shaft at a speed different from that of said first power driven shaft.

3. In combination with a rotatably mounted spindle, means for driving said spindle at a plurality of speeds comprising a power driven shaft and a second shaft having adjacent ends fitted to receive pairs of pick-off gears, intermeshing gearing between said second shaft and spindle, a third shaft having one end fitted to receive the pick-off gears otherwise placed on said power driven shaft to position said gears in meshing relation with corresponding gears fitted on said second shaft, and means for driving said third shaft from said power driven shaft including a fourth shaft, intermeshing reduction gears on said power driven shaft and fourth shaft, and intermeshing reduction gears on said fourth shaft and third shaft.

4. In combination with a rotatably mounted spindle, means for driving said spindle at a plurality of speeds comprising a power driven shaft and a second shaft having adjacent ends fitted to receive pairs of pick-off gears, intermeshing gearing between said second shaft and spindle, a third shaft having one end fitted to receive the pick-off gears otherwise placed on said power driven shaft to position said gears in meshing relation with corresponding gears fitted on said second shaft, and means for driving said third shaft from said power vdriven shaft at a speed different from that of said power driven shaft.

5. In combination `with a rotatably mounted spindle, means for driving said spindle at a plurality of speeds comprising a power drivenrshaft and a second shaft having portions tted. to receive pairs of pick-off gears, means forming-a driving connection between said second shaft and spindle, a third shaft having a portion tted to receivethe pick-off gears otherwise placed on said power driven shaft'to position Said gears in meshing relation lwith corresponding gears fitted on said second shaft, and means for driving saidr third shaft from said power driven shaft includ-` ing reduction gearing.

6. The combination of a power driven shaft and a second shaft having adjacent ends tted to receive pairs` of pick-off gears, a third shaft having one end fitted to receive the pick-off gearsr otherwise placed on said power driven shaft to position rsaid gears in meshing relation with cor# responding gears tted on said second shaft, and 

